Determinants of empirical antipseudomonal antibiotic prescription for adults with pneumonia in the emergency department

Abstract

Background: Antipseudomonal antibiotics should be restricted to patients at risk of Pseudomonas aeruginosa infection. However, the indications in different guidelines on community-acquired pneumonia (CAP) are discordant. Our objectives were to assess the prevalence of antipseudomonal antibiotic prescriptions and to identify determinants of empirical antibiotic choices in the emergency department. Methods: Observational, retrospective, one-year cohort study in hospitalized adults with pneumonia. Antibiotic choices and clinical and demographic data were recorded on a standardized form. Antibiotics with antipseudomonal activity were classified into two groups: a) β-lactam antipseudomonals (β-APS), including carbapenems, piperacillin / tazobactam or cefepime (in monotherapy or combination) and b) monotherapy with antipseudomonal quinolones. Results: Data were recorded from 549 adults with pneumonia, with Pseudomonas aeruginosa being isolated in only nine (1.6%). Most (85%) prescriptions were compliant with SEPAR guidelines and 207 (37%) patients received antibiotics with antipseudomonal activity (14% β-APS and 23% levofloxacin). The use of β-APS was independently associated with ICU admission (OR 8.16 95% CI 3.69-18.06) and prior hospitalization (OR 6.76 95% CI 3.02-15.15), while levofloxacin was associated with negative pneumococcal urine antigen tests (OR 3.41 95% CI 1.70-6.85) but negatively associated with ICU admission (OR 0.26 95% CI 0.08-0.86). None of these factors were associated with P aeruginosa episodes. In univariate analysis, prior P aeruginosa infection/colonization (2/9 vs 6/372, p = 0.013), severe COPD (3/9 vs 26/372, p = 0.024), multilobar involvement (7/9 vs 119/372, p = 0.007) and prior antibiotic (6/9 vs 109/372, p = 0.025) were significantly associated with P aeruginosa episodes. Conclusions: Antipseudomonal prescriptions were common, in spite of the very low incidence of Pseudomonas aeruginosa. The rationale for prescription was influenced by both severity-of-illness and pneumococcal urine antigen test (levofloxacin) and prior hospitalization and ICU admission (β-APS). However, these factors were not associated with P aeruginosa episodes. Only prior P aeruginosa infection/colonization and severe COPD seem to be reliable indicators in clinical practice.

Measurement of Free Plasma Concentrations of Beta-Lactam Antibiotics: An Applicability Study in Intensive Care Unit Patients

“…The frequent use of potent broad-spectrum antibiotics with antipseudomonal activity mirrors the general clinical experience but is in contrast to the very low incidence of P. aeruginosa infections in ICUs, including the local ICU. 45,46 However, there is a substantial risk of infections caused by extended spectrum beta-lactamase-expressing gram-negative pathogens in ICU patients, calling for empiric use of PIP/TAZ or rather MEM. 47 Nevertheless, P. aeruginosa is often used as a worst-case pathogen for PK/PD calculations in this setting applying the target of 100% fT .4 • ECOFF.…”

Severe community-acquired pneumonia in the post COVID-19 era

“…Angrill et al [5], determined that despite isolating Pseudomonas aeruginosa in only 1.6% of CAP episodes, around 37% of hospitalized patients were prescribed antipseudomonal antibiotics. Only prior Pseudomonas aeruginosa infection/colonization together with severe chronic obstructive pulmonary disease were found to be the most consistent risk factors for its coverage.…”